flutter_compass 0.8.1 flutter_compass: ^0.8.1 copied to clipboard
A Flutter compass. The heading varies from 0-360, 0 being north.
import 'dart:math' as math;
import 'package:flutter/material.dart';
import 'package:flutter_compass/flutter_compass.dart';
import 'package:permission_handler/permission_handler.dart';
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
const MyApp({
Key? key,
}) : super(key: key);
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
bool _hasPermissions = false;
CompassEvent? _lastRead;
DateTime? _lastReadAt;
@override
void initState() {
super.initState();
_fetchPermissionStatus();
}
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
backgroundColor: Colors.white,
appBar: AppBar(
title: const Text('Flutter Compass'),
),
body: Builder(builder: (context) {
if (_hasPermissions) {
return Column(
children: <Widget>[
_buildManualReader(),
Expanded(child: _buildCompass()),
],
);
} else {
return _buildPermissionSheet();
}
}),
),
);
}
Widget _buildManualReader() {
return Padding(
padding: const EdgeInsets.all(16.0),
child: Row(
children: <Widget>[
ElevatedButton(
child: Text('Read Value'),
onPressed: () async {
final CompassEvent tmp = await FlutterCompass.events!.first;
setState(() {
_lastRead = tmp;
_lastReadAt = DateTime.now();
});
},
),
Expanded(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(
'$_lastRead',
style: Theme.of(context).textTheme.bodySmall,
),
Text(
'$_lastReadAt',
style: Theme.of(context).textTheme.bodySmall,
),
],
),
),
),
],
),
);
}
Widget _buildCompass() {
return StreamBuilder<CompassEvent>(
stream: FlutterCompass.events,
builder: (context, snapshot) {
if (snapshot.hasError) {
return Text('Error reading heading: ${snapshot.error}');
}
if (snapshot.connectionState == ConnectionState.waiting) {
return Center(
child: CircularProgressIndicator(),
);
}
double? direction = snapshot.data!.heading;
// if direction is null, then device does not support this sensor
// show error message
if (direction == null)
return Center(
child: Text("Device does not have sensors !"),
);
return Material(
shape: CircleBorder(),
clipBehavior: Clip.antiAlias,
elevation: 4.0,
child: Container(
padding: EdgeInsets.all(16.0),
alignment: Alignment.center,
decoration: BoxDecoration(
shape: BoxShape.circle,
),
child: Transform.rotate(
angle: (direction * (math.pi / 180) * -1),
child: Image.asset('assets/compass.jpg'),
),
),
);
},
);
}
Widget _buildPermissionSheet() {
return Center(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Text('Location Permission Required'),
ElevatedButton(
child: Text('Request Permissions'),
onPressed: () {
Permission.locationWhenInUse.request().then((ignored) {
_fetchPermissionStatus();
});
},
),
SizedBox(height: 16),
ElevatedButton(
child: Text('Open App Settings'),
onPressed: () {
openAppSettings().then((opened) {
//
});
},
)
],
),
);
}
void _fetchPermissionStatus() {
Permission.locationWhenInUse.status.then((status) {
if (mounted) {
setState(() => _hasPermissions = status == PermissionStatus.granted);
}
});
}
}